The field of the present invention concerns frozen confection machines for producing ice cream bars and the like, and more specifically concerns prior art confection apparatus of the general type disclosed in the Komberec U.S. Pat. No. 3,280,763, issued on Oct. 25, 1966. In the patented device, three laterally adjacent extrusion nozzles decline from the horizontal, with the discharge ends of the nozzles overlying a conveyor having trays for receiving a semi-frozen confection continuously pumped from each nozzle in the form of an extruded column or bar. In order to slice the bar extrusions into appropriate tray lengths, a heated cutoff wire extends transversely over the conveyor and periodically descends to sever all three columns of the extruded product. Because there is a gap between adjacent trays to receive the product, the nozzles are mounted for horizontal movement and retract after a cutting operation. Thus, the nozzles initially advance in the direction of conveying movement so that the velocity of the product bar through the nozzles, plus the velocity of the nozzles themselves, is approximately equal to the tray velocity. Then the cutoff wire is swung downward to sever the extruded product bar, and retracted, following which the nozzles rapidly return to their upstream position for filling the next tray.
It can be appreciated that the combined reciprocating, oscillating and intermittent motions employed in the patented structure for coordinating the movements of the nozzles, cutoff wire and receiving trays are more complex than if the same functions might be effected with only rotary motion, and would be expecteed to require more operating components than mechanisms operating only with rotary motion. A basic object of the present invention is to provide a machine for producing slices of semi-frozen food products or the like with a fixed extrusion nozzle by slicing the moving product bar extruded from the nozzle with a heated cutoff wire having continuous rotary motion. The term slice, within the context of that term as used herein, is intended to include slices made from an extruded food product bar or the like of any cross-sectional configuration.
It is known in the prior art concerning masonry bricks to cut plastic clay material with a cutting wire mounted between two driven ring gears so arranged that the wire remains taut as the gears rotate in the same direction. This operating principle is disclosed in the Freese U.S. Pat. No. 507,798, issued on Oct. 31, 1893, for a BRICK OR TILE MACHINE. Two overlapping ring gears, rotatable abut generally horizontal axes, carry two cutting wires movable down through the gap between two horizontal conveyors. A continuous column or bar of plastic clay from an extrusion head is conveyed horizontally through one of the ring gears, and the cutting wires alternately sever the bar between the conveyors into individual bricks for subsequent firing in a kiln. In order to produce square cuts in the continuously moving bar of clay, the ring gears are inclined from the vertical so that each cutting wire, as it is moved down through the clay bar, also has a component of motion in the direction of bar motion. The horizontal motion of the cutting wire, during cutting, equals the horizontal motion of the clay bar during cutting. As a result, there is no relative horizontal motion between the wire and the moving clay bar and each cut lies in a vertical plane relative to the horizontally moving bar of clay. This principle is employed in the present invention, but the extrusion is moving down and is not supported on conveyors that prevent displacement of the product by the cutting wire.
Another prior art U.S. Pat. No. 3,554,138 to Glass issued on Jan. 12, 1971, discloses a frozen confection machine using an extruding nozzle and either a hot wire or a blade cutoff device to slice the extruded, semi-frozen product bar below the nozzle. One disadvantage of this cutoff device is that the heated wire or blade swings about the axis of a single support post, and thus has an unsupported free end. Because of this, the wire must be relatively large in diameter, or the blade wide, in order to resist flexure. In either case, the cutting is effected solely by lateral motion of the cutting member, and with relatively large frictional contact of the cutting member with the product. It has been found that with this arrangement, an indent will be formed in the product where the cutting member enters the product bar, and that a protrusion will be formed where the member exits. In other words, a severed slice will not have sharp corners where the cutting member enters and exits, and this is noticeable in the final product.
Another extrusion-type of confection machine presently in commercial use employs two opposed rotary cutting members having free ends which meet at the center of the product, and this results in a raised central ridge on the upper side of the slice, and a trough on the underside. Thus, if the objective is to attain planar surfaces where the cutting members slice the product, the dual cut is no more effective than the device disclosed in the Glass patent, supra, and also produces the unsharp corners or edges, as previously described.
It is to be noted that the cutting motion employed in the Glass and Komberec patents is what may be termed a pushing and wiping motion, since the cutoff member moves primarily in only one direction (laterally) and tends to push the product inward at initial contact, and to wipe the product outward at the point the cutting member exits.